186 Report of tuk Botanical Department of the 



GEEMINATION TESTS. 



In order to get some idea of the percentage of viable seeds in 

 samples sent to this laboratory during 1911, a comparatively small 

 number of samples were tested in the Geneva seed tester. In 

 considering the results secured it will be well to bear in mind 

 the U. S. Department of Agriculture germination standards, 

 which are, for the sorts tested: Alfalfa, red clover and timothy, 

 85-90 per ct. viable ; alsike clover, 75-80 per ct. viable. 



VIABILITY OF ALFALFA SEED SAMPLES. 



In the case of alfalfa, ten high grade samples and ten poor sam- 

 ples were selected for tests. The appearance of the seed was used 

 as the basis for the selection of these samples, the amount of im- 

 purities present being disregarded. 



Ten high grade samples. — In all of these tests duplicate sets of 

 100 seeds each were used and the duration of the test was seven 

 da vs. 



The average percentage of germination (not including hard seeds) 



was 81.9 



The average percentage (including % of hard seedb) was 87Vo 



The lowest percentage (hard seeds not viable) 56.5 



The lowest percentage (% hard seeds viable) 73. 



The highest percentage (hard seeds not viable) 92. 



The highest percentage (% hard seeds viable) 94. 



One sample contained 52Mi per ct. of hard seeds at the 

 end of the 7 day test. It is generally conceded that one-third of 

 all leguminous seeds which remain hard during a test should be 

 considered as viable. In that case the viability of this sample 

 would be 73 instead of h^V-z. In order to test this point the 

 hard seeds of the above sample were placed in moist petri 

 dishes; at the end of two months rather more than one-third of 

 them had germinated. The germination, however, was slow and 

 not vigorous. The use of seed which showed so many hard seeds 

 is not advisable. 



Ten low-grade samples. — These samples were selected because 

 of the presence of brown and shriveled alfalfa seed. The dura- 



